This invention relates to hair conditioning compositions and more specifically relates to hair conditioning compositions for use with highly alkaline hair waving or straightening compositions and to methods of waving or straightening hair under highly alkaline conditions while improving the condition of the hair.
In recent years, hair straightening has become increasingly popular in view of the hair styles which require relatively or perfectly straight hair. There are several types of hair relaxers available. One type is based on the reducing agents such as sulfites or thioglycolates which react with the disulfide bond of hair keratin to form sulfhydryl or reduced hair. While the majority of home straightening kits are based on the sulfite or thioglycolate straighteners, there are several disadvantages inherent in their use. The major disadvantage is the highly offensive odor of the thioglycolate solutions, themselves, and of the reduced hair produced by either the sulfite or the thioglycolate solutions. The second disadvantage is that they require the use of an oxidizing neutralizer, such as hydrogen peroxide, to re-establish the disulfide linkages and stop the straightening process. The neutralizer must then be removed and the entire straightening process is then followed by shampooing.
Sodium hydroxide-based hair straightening or relaxer kits became available in 1958, and today, essentially all of the chemical hair straighteners used in professional shops are based on sodium hydroxide. The sodium hydroxide-based relaxer was introduced to the retail market in 1971 and has gained popularity in home use since that time. Sodium hydroxide based relaxers generally contain petrolatum and/or mineral oil to reduce their caustic effect and contain anionic surfactant and sometimes a non-ionic surfactant for improved wettability of the composition.
Fatty alcohols, lanolin, ethoxylated fatty alcohols, ethoxylated lanolin, stearic acid, and protein hydrolyzates have also been used in aqueous sodium hydroxide-based hair relaxers, in addition to color and fragrance additives.
Aside from their causticity, the principal disadvantage of sodium hydroxide-based relaxers is that they leave the hair in a brittle state and harsh to the touch.
Despite the disadvantages of the sodium hydroxide relaxers, they have several advantages over the sulfite or thioglycolate relaxing agents and would be far superior for home and beauty shop use if the problem of harshness to the hair could be overcome. The sodium hydroxide relaxers do not have a highly objectionable odor or cause such an odor by reducing the hair, and, as sodium hydroxide straightened hair is already cross-linked by a lanthionine linkage, the only step required following the straightening process is to shampoo the hair with an acidic shampoo to remove the excess alkaline solution.
Modernly, there has also been a growing demand for hair products which protect and condition the hair, leaving the hair soft and manageable as well as straightening or waving it, and a number of hair conditioning agents and compositions have been developed and marketed. Sokol, U.S. Pat. No. 3,912,808, discloses the use of certain water soluble quaternary, cationic polymers which modify the surface characteristics of hair and improve its condition, and further discloses the incorporation of the polymers in hair waving and straightening compositions based on the reducing agents capable of reducing the disulfide linkages in hair keratin, such as the odiferous thioglycolates or odor causing sulfites. However, the Sokol patent teaches that the cationic polymers may only be effectively employed in aqueous solutions of pH 1.5 to 11.5 (column 3, lines 3 to 4). We have surprisingly found that some of the polymers disclosed in the Sokol patent may be effectively employed with highly alkaline solutions of pH 12 to 13. This is unexpected as a solution of pH 12 is three times as alkaline as a solution of pH 11.5 and one would expect the cationic polymer to be adversely affected by a threefold or more increase in alkalinity.
We have also found that sodium hydroxide-based relaxing or waving solutions can be adapted for safe and effective use by incorporating therein materials which protect the users' hair.
Thus, the present invention provides a solution to a long standing need by providing improved compositions and methods employing highly alkaline straightening or waving agents.